Project Summary/Abstract Bacteria mount a physiologic stress response to survive hostile or stringent conditions. These stress responses shape the microbial communities that live in, on, and around us. Despite the importance of stress responses, we know little about how microbes tolerate complex combinations of stressors. This proposal will answer three overarching questions regarding microbial stress responses. 1.) How do bacteria response to multiple stressors? 2.) How does stress reshape the composition and stability of microbial communities? 3.) How quickly can we learn the stress responses of newly discovered bacteria? In answering these questions, several hypotheses will be evaluated using a consistent experimental and theoretical framework. The stress response networks of pathogenic streptococci will be characterized across multiple scales. Long term, our goal is to develop tools to analyze and target complex stress responses in the human microbiome.